Method of treating glycerin.



S. H. PLEMING.

METHOD 0F TBEATING GLYCERIN.

APPLICATION FILED HAY 27, 1909.

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Be it known that I, SAMUEL HENRY FLEM` UNITED A STATES PATENT oEFTcE.

SAMIJ'EL HENRYI FLEMING, OF CAM'DEN, NEW JERSEY, ASSIGNOR TO E. I. DU PONT DE NEMOURS POWDER COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION 0F 'NEW JERSEY.

METHOD OF TREATING GLYCERIN.

ING, a citizen of the United States, residing at Camden, county of Camden, and State of New Jersey, have invented a new and useful Improvement in Methods of Treating Glycerin, of which the following is a full, clear, and exact description.

Polymerizedlglycerin or poly-glycerin is a term used for a glycerin in which, as is generally supposed, two or more of the glycerin molecules are combined together. Heretofore this reaction has been produced by subjecting glycerin either alone or admixed with an alkali, such, -for instance, as caustic soda, NaOH, to the action of heat under at- Inospheric pressure.

' I have discovered that if the lreaction takes place under a pressure lem than atmospheric, the temperature required to produce the product' may be brought so low as not to break up or tend to break up the glycerin, as occurs in the ordinary method of carrying out this reaction. By this I am enabled to produce the. react-ion and the product without having any deleterious by-products in any quantity. Further, by carryingout this process as described a higher polymerization of the glycerin is obtained. The glycerin alone may be acted on or a condensing reagent may be added, such, for instance, as caustic soda or the ac tate reagent of my application filed May 2 th,` 1909, Serial No.

` v1% of sodium acetate.

498,749. In that application I add sodium acetate N-aCgHsO2 1n quantity of one-half ,to one per cent. of the weight of the glycerin.

In carrying out my invention I have used `a partialvacuum of apressure ofive inches of mercury and also ten inches of mercury, both with good results.

The following is an example of my processswhen I use sodium acetate as the reagent. I take glycerin of the grade known `as dynamite glycerin, which is of about 98 to 99% purity,l andv I add about .5% to The pressure in the vessel is reduced by closing -it to the air, and by a vacuum pumpredueing the internal pressure. This vessel is then subjected to heat. I have found the preferred Work-A ing pressure to be an absolute pressure of 5 to 10 inches of mercury, and the glycerin is. raised to the boiling point under that Specicatiron of Letters Patent. Patented Dec, App1icetion led May 27, 1909. Serial No. 498,717.

| pressure, which, at xinches of mercury, would be in the neighborhood of 230o C. As polymerization progresses, the temperature will rise, even when the pressure is maintained constant onl account of the increase in the amount of polymerized glycerin. When I use an absolute pressure of 10 inches of mercury the boiling point at the commencement of the operation, will be in the neighborhood of 245 C. or 250 C. Ijlere also the temperature rises as the reactlon progresses.

When I speak of an absolute pressure of 5 inches I mean a pressure Vof about 25 inches of mercury below atmospheric pressure, which is an absolute pressure of about 30 yinches of mercury.

The sodium acetate may be used either in a crystallized or anhydrous form. I have used both.

I will now-describe an apparatus by the use of which my invention may be carried out.

In the drawings: Figure l is a sectional elevation of the apparatus for carrying out my invention, in which the ordinary horizontal condenser is used. Fig. 2 is a sectional elevation of the apparatus when a return condenser is used.

In using the apparatusin Fig. 1, the glycerin is placed in the reaction vessel a which is heated by any appropriate means, not shown. Any vapors not condensed by the walls and top of vessel a are carried is kept at the proper temperature to condense as far as possible the glycerin vapor, without condensing the aqueous vapor. The cooling water enters condenser c by pipe g and leaves by pipe h. The condensed glycerin and the water vapor pass from the co'ndenser c through pipe m to vessel (Z, whence the glycerin may be drawn through cock e and returned to vessel a if desired. The water vapor passes on through pipe to vessel j, where it is condensed. Pipe lc leads romvessel j to the vacuum pump Z.

Fig. 2 shows a reaction vessel a as above, and a return condenser c, which is main- `tained at such a temperature as to condense the. glycerin vapors, the glycerin flowing back to vessel a, while the water vapor passes on. Here again the cooling water enters the conoil by the pipe b to the condenser c, which Y condensing reagent to lieat Wllen under a l pressure less than atmospheric.

In testimony of which invention, I have hereunto set'my hand, at Camden, on this 21st day of May, 1909.

SAMUEL. HENRY FLEMING. Witnesses: y

AUGUST SEEMAN, F. B. HOLMES.` 

